Field of the Disclosure
The present embodiments relate to the field of circuit protection devices. More particularly, the present embodiments relate to a protection device providing overcurrent protection by triggering a resistance change.
Discussion of Related Art
Circuit protection devices form an electrical connection with a component or components in a circuit to be protected. Certain of these protection devices are used to protect circuits from excessive current while other devices may provide protection against overvoltage transients when a voltage spike occurs. One type of device used for overvoltage protection is a Zener diode which is designed to have a specific reverse breakdown voltage which is the conduction voltage when the diode is reverse biased. This is controlled by doping of the p-n junction allowing electrons to tunnel from the p-type material to the n-type material. Another type of overvoltage protection device is an avalanche breakdown diode which operates in carrier impact multiplication at avalanche breakdown when an overvoltage condition occurs.
Fuses (or fusible links) represent a common type of protection device used to limit or terminate current. A fuse may limit or terminate current by providing an open circuit when current conducted through the fuse exceeds a predetermined limit, which varies among different fuses according to the fuse rating. While the fuse action may be useful to ensure that current that may conducted through a device or circuits to be protected does not exceed a safe value, one disadvantage is that once the fuse opens, the protected elements may be rendered inactive until fuse replacement. While certain types of overvoltage protection devices may be reversible, an overvoltage protection device may not serve the same over current protection functions as a fuse may supply. It is with respect to these and other considerations that the present improvements have been needed.